“The Mortal Instruments: City of Bones” is the film adaptation of a book in the young adult urban fantasy genre. The book is the first of five, soon to be six, in a series. There is also a prequel trilogy set in the Victorian Era, and a planned sequel trilogy set in the near-term future. So fans will have a lot to look forward to if “City of Bones” is a box-office success.

I haven’t read any of them.

This presents a problem only insofar as I can’t speak to how well and faithfully the movie was adapted from the book. I can say I haven’t yet heard any reports of an outraged author, Cassandra Clare (nee Judith Rumelt).

Interestingly the books include some references and cross-characters to works by Clare’s friend Holly Black, author of “The Spiderwick Chronicles” and other children’s fantasy.

There is, as several critics have noted, virtually nothing original about the plot devices in “City of Bones.”

That’s not necessarily bad though. Mythic material is part of our common heritage, stories we’ve heard many times before and never grow tired of hearing. Writers like Charles DeLint and Stephen King have done wonderful treatments of old familiar stories such as “The Little Mermaid” and “The Monkey’s Paw” respectively.

What matters is how well the material is adapted for modern audiences, and here I’m going to have to say the jury is still out.

The plot elements are all there: the tribes of faerie, the hidden world coexisting with our own, the young hero unaware of her heritage coming into her own and discovering her powers, the identity of the true father, the quest for the objects of power.

Clarissa “Clary” Fray (Lilly Collins) is a teenage girl living with her mother Jocelyn (Lena Headey). She has no father but mom’s boyfriend Luke Garroway (Aidan Turner) serves as a father figure. Her best and only friend is Simon Lewis (Robert Sheehan) a nerdy boy who is, obvious to everyone but her, smitten with her.

Clary is having more than the usual teenage problems though. She starts to compulsively sketch a peculiar rune and she sees people others can’t see. Then she sees one of the people only she can see kill someone only she can see.

That person is Jace Wayland (Jamie Campbell Bower) a shadow hunter.

Clary it seems is also a shadow hunter, a race of half-angelic beings who hunt demons. Furthermore, her mother has had he memory blocked by a powerful wizard.

Of course the course of true love can never run smooth. It seems there’s a teensy little problem here, Jace may be her brother.

Oh yes, and Jace has a partner, a guy who’s secretly crushing on him (Kevin Zegers). Gay is evidently a big no-no among shadow hunters.

Not to mention they are apparently the children of the main villain, Valentine (Jonathan Rhys Meyers).

Valentine is a former shadow hunter who wants the objects of power, in this case the Mortal Cup that can change mundanes (that’s us normal folks) into half-angels. Valentine is willing to deal with demons to get it.

There is much to like about “City of Bones.” The magic starts out visually understated without an over-reliance on special effects. The transition from Brooklyn to the hidden world is quite stunning. The characters are appealing enough. Lilly Collins is still the adorable pixie she was in “Mirror Mirror” it’s hard to realize she’s 24.

Some stuff doesn’t jibe. What are all the British accents doing in New York?

When Jase and Clary are enjoying a first kiss at Clary’s door and Simon opens it on them, Jase reacts like an child rather than a warrior seasoned by a life of fighting demons. It’s quite frankly painful to watch.

There are said to be three objects of power, the first of which is the Mortal Cup. I’ve peeked at the book blubs and another is a sword. That’s two out of four suits of the Tarot cards, which figure prominently in the movie. The others are wands and coins. So is there a fourth?

This series has promise, even if you haven’t read the books.

Quibbles? It’s nothing I wouldn’t be perfectly happy with my children seeing. I just wish there was more heroism and less teen angst and I wish the mythic material hung together a bit better.

And I think it’s kind of chickenpoop to have angels and demons, but no mention of God or Satan.